package com.example.demo.leetcode.classics150;

/**
 * ******************************************************
 *
 * @author liugh9
 * @version 1.0
 * @classname _146交错字符串
 * @description
 * @date 2023/08/28 10:39
 * <p>
 * ******************************************************
 */
public class _146交错字符串 {

    public boolean isInterleave(String s1, String s2, String s3) {
        int m = s1.length(), n = s2.length();
        if (s3.length() != m + n) return false;
        // 动态规划，dp[i,j]表示s1前i字符能与s2前j字符组成s3前i+j个字符；
        boolean[][] dp = new boolean[m + 1][n + 1];
        dp[0][0] = true;
        for (int i = 1; i <= m && s1.charAt(i - 1) == s3.charAt(i - 1); i++) dp[i][0] = true; // 不相符直接终止
        for (int j = 1; j <= n && s2.charAt(j - 1) == s3.charAt(j - 1); j++) dp[0][j] = true; // 不相符直接终止
        for (int i = 1; i <= m; i++) {
            for (int j = 1; j <= n; j++) {
                dp[i][j] = (dp[i - 1][j] && s3.charAt(i + j - 1) == s1.charAt(i - 1))
                        || (dp[i][j - 1] && s3.charAt(i + j - 1) == s2.charAt(j - 1));
            }
        }
        return dp[m][n];
    }

}
